The present invention relates to improvements in polyester fiberfill structures and articles made therefrom. Further, the invention relates to improved processes for making polyester fiberfill structures and articles from such structures. These articles are suitable for both domestic and industrial end use, such as pillows, sleeping bags, car seats, insulation, quilts, apparel, filters and the like.
Polyester fiberfill is used commercially in many garments and other articles because of its desirable thermal insulating and aesthetic properties. Polyester fiberfill is generally used commercially in garments in the form of bulky quilted batts (sometimes referred to as batting). Most commercial polyester fiberfill has been in the form of crimped polyester staple fiber. Another commercial use for polyester fiberfill is in the form of a corrugated fibrous batting/structure.
A known process and apparatus used for consolidation of bulky fibrous webs into a corrugated structure is disclosed in Krema et. al., EP-0-648-877-B1. This document does not disclose any desired properties of the corrugated structure to be obtained or any products to be made from the structure formed. Similarly, a device for forming sheets of fibrous web, where the web is vertically folded, is disclosed in International Application No. WO/99/61693 by Jirsak et al. Jirsak et. al., like Krema et al., does not disclose any desired properties of the fibrous batting to be obtained or any products to be made from the structure formed.
Frederick et al., U.S. Pat. No. 2,689,811 also discloses a method of making corrugated fibrous battings. However, although Frederick states that its corrugated battings are of loose construction and have very low bulk density, this document also does not teach or suggest any desired properties of the corrugated structure to be obtained or any products to be made from the structure formed.
Other attempts at producing variable density, corrugated resin-bonded or thermo-bonded fiberfill structures are disclosed in Chien, U.S. Pat. No. 5,702,801 and Chien et al., U.S. Pat. No. 5,558,924. Chien ""801 discloses a method of corrugating bonded polyester fiberfill that enhances the final product""s three-dimensional strength and resilience with respect to other methods. The fiberfill is stated as being used for products such as quilts, pillows, cushion seats and sleeping bags. The fibrous webs are folded to form a plurality of pleats having alternating crests and bases. However, since the carded fibrous webs used in Chien are cross-lapped (25 layers) before being corrugated in a stuffer box type crimper mechanism, the resulting bulk density of the structure formed is very high, i.e. 15-25 kg/m3, resulting in a very hard and undesirable quality of the material for some enduse applications.
Chien et al. ""924 discloses a method of forming a corrugated structure from a fibrous web that results from a stuffer box type crimper mechanism. This structure from the stuffer box is stated as being used for products such as quilts, pillows, cushion seats, or sleeping bags. However, the process used in this document also uses carded fibrous webs which are cross-lapped before being corrugated in a stuffer box type crimper mechanism, resulting in limited properties of the structure formed, such as the height of the product produced being limited to between 1.95 inches (49.5 mm) and 2.11 inches (53.6 mm), due to the high bulk density of the product.
Therefore, there is a need for providing polyester fiberfill corrugated structures having desired performance for use, for example, in pillows, and methods of making such structures. Such performance is indicated by characteristics including loft/bulk, comfort, softness, durability and insulation.
The present invention solves the problems associated with the prior art by providing articles which have desired performance with respect to loft/bulk, comfort, resiliency, softness, durability and insulation. Applicant has found that such performance is achieved by a combination of certain structure bulk density, height and peak frequency. Moreover, Applicant has found that such performance is achieved when such structures are made from fibers with certain denier per filament, crimps per inch and crimp take-up. Applicant has measured performance in pillows in terms of three variables, namely, energy required for compression, WC, linearity of the resulting product, LC, and resiliency of the resulting product, RC.
Therefore, in accordance with the present invention there is provided a corrugated fiberfill structure having a configuration of essentially lengthwise rectangular cross section, with continuous parallel alternating peaks and valleys of approximately equal spacing, and a plurality of vertically aligned pleats which extend between each peak and each valley, the structure having a bulk density of about 5 to about 18 kg/m3, a height of about 10 mm to about 50 mm and a peak frequency which occurs at about 4 to about 15 times per inch (1.58-5.91 times per cm). The fiberfill of this corrugated structure comprises fibers with a denier per filament of about 0.5 to about 30 (0.55-33 decitex per filament), crimps per inch of about 4 to about 15 (1.58-5.91 crimps per cm), and a crimp take-up of about 29% to about 40%. There is also provided a pillow having a corrugated structure having this bulk density, height and peak frequency, and made from a fiber having this denier per filament, crimps per inch and crimp take-up. This pillow has an energy for compression in the range of 0.253-0.584 lb/in2xc3x97in/in (17.79-41.06 gm/cm2xc3x97cm/cm ), linearity in the range of 0.480-0.678 and a resiliency in the range of 0.448-0.639.
Further in accordance with the present invention, there is provided a process for forming a corrugated fiberfill structure comprising feeding clumps of fiber stock from a bale comprising fiberfill material and a binder fiber to a picker where the fiberfill material and the binder fiber are opened up; feeding the opened up fiberfill material and the binder fiber to a blender to obtain a uniform mixture; carding the blend to form a fibrous web; vertically folding the fibrous web to form a closely packed, corrugated fiberfill structure having a configuration of essentially lengthwise rectangular cross-section having continuous alternating peaks and valleys of approximately equal spacing, and a plurality of vertically aligned pleats which extend between each peak and valley; heating the corrugated fiberfill structure to bond the binder fibers and the fiberfill material so that the structure is consolidated and maintains its corrugations, wherein the structure has a bulk density of about 5 to about 18 kg/m3, a height of about 10 mm to about 50 mm and a peak frequency which occurs at about 4 to about 15 times per inch (1.58-5.91 times per cm).